Get to know your Cosy heat pump
Stay cosy and in control with guidance and support on how to use your Cosy heat pump
Find what you need
Cosy support pages
The Cosy controls guide
Run through the different controls, what they're for and how you use them.
How to set a schedule on Cosy Octopus
Check out our recommended schedule for the Cosy Octopus tariff.
Getting started: what you need to know
Head back for advice on saving money and how the heat pump works in your home.
Troubleshooting
If your property is achieving its target temperature, there’s nothing to worry about! Heat pumps use a smart feature called weather compensation to help your heat pump run more efficiently. Weather compensation automatically adjusts the flow temperature based on the outdoor temperature which can mean your radiators are cooler to touch than you may expect.
Check your temperature sensor position. Try to leave this in a neutral position in the property and not a place where the temperature can change a lot e.g., next to an external door in the hall, next to the stove in the kitchen.
Ensure you have a suitable heating schedule.You can find guidance on how to use the Cosy controls here, and recommendations for how to set a schedule on the Cosy Octopus tariff here.
Heat pumps are designed according to MCS guidance which suggests non-habitable rooms (hall, kitchen, landing, toilet) achieve 18°C and habitable rooms (living room, dining room & bathrooms) achieve 21-22°C. Please remember this when setting the target temperature as you may struggle to achieve a target temperature of 22°C in a hall.
Ensure your weather compensation is set correctly. If you have changed your weather compensation settings since your commissioning, this could affect your heat pump being able to achieve your target temperature.
Keep your TRVs (thermostatic radiator valves) on your radiators open. If they are closed, this will limit the flow of hot water to your radiators and mean less heat is dispersed in your property.
Check the power supply. This could be due to loss of electricity supply.
_C_heck both the indoor (cylinder) and outdoor (heat pump) units are switched on and check your app is connecting to the system.
Next, check your circuit breaker box for a tripped circuit. If there’s not an issue with either then contact us for advice.
This is fairly normal due to heat pumps having a slightly higher pump speed than boilers. There might be air in your heating system meaning your heat pump is having to work harder than usual.
Action: open the auto air vents on the sides of your radiators and ensure all air is removed, this is also known as “bleeding your radiators” - How To Easily Bleed A Radiator
If you still feel there is excessive noise, contact us for help.
Our design ensures you should always have enough hot water and we’ve created a handy guide explaining how cylinder work - Cylinder Guide
If you need extra hot water (e.g., guests visiting), you can follow the tips below:
Make sure the hot water is up to your set temperature before everyone starts taking baths/showers
Extend the heating schedule: keep the hot water schedule on a bit longer so your heat pump continues generating hot water during the peak period (if you’re on Cosy Octopus).
It’s normal for heat pumps to create water while operating but this should drain away easily from the drain pipe fitted to the back of your heat pump. If you’ve found a puddle of water, check that there’s no obvious debris or blockage of the drain pipe, and carefully clear away any you do find. If you can’t see anything, or you’ve spotted a leak, contact us - don’t try to fix it yourself.
Occasionally in very cold weather the drainage pipe may freeze and you’ll find a build up of water - Don’t worry, the heat pump will continue to work and it will defrost when temperature increases.
You’ll get used to the way your heat pump sounds when it’s working as it should. But sounds that are unfamiliar can tell you that your heat pump needs some attention.
Loud gurgling, grinding or squealing sounds are likely telling you that your heat pump is struggling and has a problem that we’ll need to fix.
In colder weather your heat pump will be working harder so it may seem louder than usual. This is especially true if it’s one of the first cold days of the year.
Action: There might be air in your heating system meaning your heat pump is having to work harder than usual. Open the auto air vents on the sides of your radiators and ensure all air is removed, this is also known as “bleeding your radiators” - How To Easily Bleed A Radiator
Action: If you feel there is excessive noise, give us a call.
It’s most likely defrosting. When it’s cold, your pump will automatically run a cycle to clear any built-up ice. It’s actually steam, not smoke, and a bit of melted ice. So it might look a bit dramatic, but it’s actually a sign everything’s working as it should be.
Ice on the back of your heat pump, especially during cold weather, is often a sign of a normal defrost cycle.
If you feel there is excessive icing or icing in warmer weather could indicate a problem like poor airflow or low refrigerant, contact us for help.
If the heat pump is running constantly your thermostat could be set too high.
Action: Check the thermostat temperature and that they’re working correctly.
Action: : Make sure you check your Cosy Pods to make sure the “Boost” function isn’t on. If it isn’t, take a look at your Cosy Hub in case there are any fault indications showing. If everything looks to be working with your thermostat and Cosy controllers, contact us for help.
Still feel like something’s not right? Get in touch
If you can't find what you're looking for, get in touch...
Call us: 0808 196 6842
Email us heat@octopus.energy
Our aftercare phone lines are open 8am – 8pm Monday to Saturday, 10am - 6pm Sunday. There are other ways to get in touch too.
If you'd like to make a complaint, find our complaints procedure here.
User Guides
Cosy heat pump customers on the Cosy Octopus tariff saved an average of £200 last year compared to using a gas boiler running at 85% efficiency on our standard variable tariff
This figure is based on the actual energy consumption of all Cosy heat pump customers on a Cosy Octopus tariff between 1 July 2025 and 1 July 2026, using tariff rates at the time.
We compared this to the cost of producing the same amount of heat with a gas boiler operating at 85% efficiency, priced using our Flexible Octopus (standard variable) tariff at the same time.
Savings from gas standing charges were included only for customers who had fully removed their gas supply (less than 3% of customers). Actual savings vary depending on system design, tariff choice, home insulation, and energy use.
Our typical heat pump price is £4,459, which is lower than the national average of £5,600
This is the median post-survey price from all of our heat pump quotes after the £7,500 Boiler Upgrade Scheme has been applied, between 01/09/2025 and 28/02/2026. The national average is taken from the Boiler Upgrade Scheme statistics: April 2026 – median cost of installation Q4 2025.
Cut carbon emissions by 82% with a heat pump
This is the typical reduction in heating carbon emissions using an electric powered heat pump compared to a gas boiler.
The carbon breakdown
Gas CO2 (tonnes per year) - 2.42
Electricity CO2 (tonnes per year) - 0.43
Carbon saving (tonnes per year) - 1.99
Data sources and assumptions
Gas Energy Usage (kWh) 11500 (Ofgem medium use gas usage (Jun 2026))
Heat Pump Efficiency 312% (typical seasonal coefficient of performance from a fleet of Octopus high temperature heat pumps)
Gas Boiler Efficiency 85% (The typical gas boiler efficiency from a BEIS study)
Gas fuel emissions of (gCO2/kWh) 210 (SAP 10.2)
Electricity fuel emissions of (gCO2/kWh) 136 (SAP 10.2)
Based on these sources, heat pumps typically produce lower operational emissions when heating the home than gas boilers.
For more information, explore our Octopus Cosy heat pump fleet performance dashboard.
We're the largest heat pump installer on the Boiler Upgrade Scheme
Based on Octopus benchmarking against Ofgem reports from 2024, and we've continued to grow since.
Our customers love their heat pumps!
- 93% of people say it's the same or more comfortable than their previous boiler
- 87% say it costs the same to run or less
- 83% say it's the same noise or less than the previous boiler
- 90% say it's just as easy or easier to maintain
We survey all our heat pump customers 3 months post-installation to see how they find their heat pump compared to their previous gas boiler. Survey results are taken from a sample of 2,837 customers:
Comfort: 93% of people say it is the same or more comfortable than their previous boiler.
Running Costs: 87% say it costs the same to run or less.
Noise: 83% say it is the same noise or less than the previous boiler.
Maintenance: 90% say it is just as easy or easier to maintain.
A heat pump is around 4x more efficient than a gas boiler
Heat pumps don't generate heat by burning fuel. Instead, they transfer existing heat into your home. This means they can deliver multiple units of heat for each unit of electricity used.
Based on performance data from a fleet of installed Octopus Cosy heat pumps, typical real-world seasonal performance (SPF or SCOP) is around 3.6. This means around 3–4 kWh of heat is delivered for every 1 kWh of electricity used (an effective efficiency of 300–400%). By comparison, typical UK domestic gas boilers operate at around 85% efficiency, delivering approximately 0.85 kWh of heat per 1 kWh of gas used. On this basis, a heat pump can be around 4× more efficient than a typical gas boiler.
All our heat pumps are independently tested by the Building Research Establishment (BRE), with SCOP values published on the Microgeneration Certification Scheme (MCS) product database. Actual efficiency will vary depending on the property, system design, and usage. For more information, explore our Octopus Cosy heat pump fleet performance dashboard.
The UK's most awarded energy supplier
We've won more awards for customer service than anyone else.
Heat pumps give reliable, consistent heating and hot water
The heat pump user survey report by Nesta from May 2023 summarises that "users are highly satisfied with their heat pumps". It states: "People living in England, Scotland and Wales who own their home and use a heat pump to heat it are satisfied that heat pumps are safe, reliable, quiet heat sources that are effective for space heating and producing hot water." Find the full report here.
The Cosy heat pump is quiet
Heat pump sound power levels are verified by an independent, third-party laboratory as part of the testing process for inclusion on the MCS product database. The laboratory verifies the sound power on the A-weighted decibel curve, as A-weighting closely aligns to how humans perceive "loudness".
All heat pumps are measured using EN14511 standards to ensure uniformity across manufacturers and models. Our Cosy 6 heat pump has a verified sound power level lower than many other heat pumps of the same capacity.
Heat pump heating makes the air healthier in your home
Homes with a heat pump emit far less harmful nitrous oxide (NOx) emissions than those with gas boilers and cookers, significantly reducing asthma and other respiratory illnesses. According to the Sustainable Markets Initiative Cleantech Homes report.
A heat pump can add thousands to your property value
Analysis by the Department of Land Economy at the University of Cambridge suggests a 16% value uplift for new-build homes with enough solar and battery storage to eliminate energy bills. A further study of over five million existing properties indicates a 2-3% value increase for existing homes with solar panels or heat pumps (versus like-for-like gas-heated homes), according to the Sustainable Markets Initiative: Cleantech Homes report, 2024.
As of April 2025, the average house price in the UK is £265,497 according to the Land Registry. Therefore, a 2-3% value increase for an average house priced at £265,497 would be between £5,310 and £7,965.
Heat pumps typically last longer than gas boilers
The expected lifespan of a typical gas boiler is 10–15 years. A heat pump typically has a lifespan of 15–20 years, with UK government research indicating an average of around 20 years. Manufacturer Daikin reports similar ranges. Actual lifespan depends on factors such as installation quality, maintenance, usage patterns, and operating conditions.